Sqlite databse not creating after build WPF application

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my project is working fine in visual studio. after build the application Sqlite database are not creating, when i run application its crash when the sqlite connection start.
i dont know how to handle this.
please give a any solution for this.

What I have tried:

public void database()
        {
            connection = new SQLiteConnection("Data source=user_accounts.db; Version=3; New=True; Compress=True;");
            connection.Open();
            command = connection.CreateCommand();
            command.CommandText = "CREATE TABLE IF NOT EXISTS Registered_Accounts(id integer primary key, user_name TEXT, user_password TEXT)";
            command.ExecuteNonQuery();
           
}


 public bool cheackAccountStatus(string username, string password)
        {
            command = new SQLiteCommand("SELECT * FROM Registered_Accounts where user_name ='" + username + "' and user_password='" + password + "'", connection);
            bool returnValue = false;
            reader = command.ExecuteReader();

            if (reader.HasRows)
            {
                reader.Close();
                returnValue = true;
            }

            else
            {
                database();
                string userdata = "INSERT INTO Registered_Accounts(user_name, user_password) values('" + username + "', '" + password + "')";
                command.CommandText = userdata;
                command.ExecuteNonQuery();
                reader.Close();
                returnValue = false;
            }
            return returnValue;
        }

Posted 21-Apr-21 20:46pm

Member 15079856

Updated 21-Apr-21 21:03pm

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OriginalGriff · Answer 1 · 2021-04-21T21:03:00

Start by finding out why it crashed: use a try ... catch block around the body of your database and cheackAccountStatus methods, and log or display the error details in the catch block.
Use the debugger to examine the Exception object to see if there is Inner Exception information as well.

The error detail is important: it tells you why the app failed to do something - and until you have that, there is nothing sensible anyone can do.

When you have the error info, think about what it says, and try to work out why. My guess - and that's all it can possibly be - is that the error info will be complaining that the file doesn't exist - and that means you need to create it!

But don't do your code like that!
1) Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.

When you concatenate strings, you cause problems because SQL receives commands like:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'

The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;--'

Which SQL sees as three separate commands:

SQL

SELECT * FROM MyTable WHERE StreetAddress = 'x';

A perfectly valid SELECT

SQL

DROP TABLE MyTable;

A perfectly valid "delete the table" command

SQL

--'

And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.

So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?

2) Never store passwords in clear text - it is a major security risk. There is some information on how to do it here: Password Storage: How to do it.[^]

And remember: if you have any European Union users then GDPR applies and that means you need to handle passwords as sensitive data and store them in a safe and secure manner. Text is neither of those and the fines can be .... um ... outstanding. In December 2018 a German company received a relatively low fine of €20,000 for just that.